International trade depends on the concept of comparative cost advantage. This means that different countries have different production costs and therefore can produce certain goods more efficiently and at a lower cost compared to other countries. When countries specialize in producing goods they have a comparative cost advantage in, they can trade with other countries to obtain goods they don't produce efficiently or at all. For example, if Country A is better at producing wheat and Country B is better at producing cloth, Country A can specialize in producing wheat and trade it with Country B in exchange for cloth. This allows both countries to consume more goods at a lower overall cost compared to producing everything domestically. Comparative cost advantage helps to increase efficiency and maximize production across different countries, leading to increased economic growth and development.